Within the field of computing, many systems exist that can infer information about an individual based on various signals and use such information to provide the individual with enhanced services and personalized content. For example, an e-commerce Web site may recommend products of interest to an individual based on inferences drawn from the individual's previous purchases. As another example, a search engine may personalize search results and related content to a user based on inferences made regarding the user. Traditionally, search engines derive such inferences from user queries, clicks, views, and occasionally by data mining social networks.